The scrits themselves will use ssh to connect to every machine (even
localhost).
It's up to you if you want to type the password everytime. For a
pseudo-distributed system, I don't see the issue with configuring a local
ssh access.
BUT Hadoop in itself does not require ssh. If you have a more appropriate
way to start/stop the processes, you can write your own scripts.
Regards
Bertrand
On Thu, May 16, 2013 at 6:02 PM, Mohammad Tariq <dontariq@gmail.com> wrote:
> Hello Raj,
>
> ssh is actually 2 things :
> 1- ssh : The command we use to connect to remote machines - the client.
> 2- sshd : The daemon that is running on the server and allows clients to
> connect to the server.
> ssh is pre-enabled on Linux, but in order to start sshd daemon, we need to
> install ssh first.
>
> To start the Hadoop daemons you have to make ssh passwordless and issue
> bin/start-dfs.sh and bin/start-mapred.sh.
>
> You might find this link<http://cloudfront.blogspot.in/2012/07/how-to-setup-and-configure-ssh-on-ubuntu.html#.UZUCkUAW38s>
> useful.
>
> Warm Regards,
> Tariq
> cloudfront.blogspot.com
>
>
> On Thu, May 16, 2013 at 9:26 PM, Raj Hadoop <hadoopraj@yahoo.com> wrote:
>
>> Hi,
>>
>> I am a bit confused here. I am planning to run on a single machine.
>>
>> So what should i do to start hadoop processes. How should I do an SSH?
>> Can you please breifly explain me what SSH is?
>>
>> Thanks,
>> Raj
>> *From:* Jay Vyas <jayunit100@gmail.com>
>> *To:* "common-user@hadoop.apache.org" <user@hadoop.apache.org>
>> *Cc:* Raj Hadoop <hadoopraj@yahoo.com>
>> *Sent:* Thursday, May 16, 2013 11:34 AM
>> *Subject:* Re: Configuring SSH - is it required? for a psedo
>> distriburted mode?
>>
>> Actually, I should amend my statement -- SSH is required, but
>> passwordless ssh (i guess) you can live without if you are willing to enter
>> your password for each process that gets started.
>>
>> But Why wouldn't you want to implement passwordless ssh in a pseudo
>> distributed cluster ? Its very easy to implement on a single node:
>>
>> cat ~/.ssh/id_rsa.pub /root/.ssh/authorized_keys
>>
>>
>>
>>
>> On Thu, May 16, 2013 at 11:31 AM, Jay Vyas <jayunit100@gmail.com> wrote:
>>
>> Yes it is required -- in psuedodistributed node the jobtracker is not
>> necessarily aware that the task trackers / data nodes are on the same
>> machine, and will thus attempt to ssh into them when starting the
>> respective deamons etc (i.e. start-all.sh)
>>
>>
>> On Thu, May 16, 2013 at 11:21 AM, kishore alajangi <
>> alajangikishore@gmail.com> wrote:
>>
>> When you start the hadoop procecess, each process will ask the password
>> to start, to overcome this we will configure SSH if you use single node or
>> multiple nodes for each process, if you can enter the password for each
>> process Its not a mandatory even if you use multiple systems.
>>
>> Thanks,
>> Kishore.
>>
>>
>> On Thu, May 16, 2013 at 8:24 PM, Raj Hadoop <hadoopraj@yahoo.com> wrote:
>>
>> Hi,
>>
>> I have a dedicated user on Linux server for hadoop. I am installing it in
>> psedo distributed mode on this box. I want to test my programs on this
>> machine. But i see that in installation steps - they were mentioned that
>> SSH needs to be configured. If it is single node, I dont require it
>> ...right? Please advise.
>>
>> I was looking at this site
>>
>> http://www.michael-noll.com/tutorials/running-hadoop-on-ubuntu-linux-single-node-cluster/
>>
>> It menionted like this -
>> "
>> Hadoop requires SSH access to manage its nodes, i.e. remote machines plus
>> your local machine if you want to use Hadoop on it (which is what we want
>> to do in this short tutorial). For our single-node setup of Hadoop, we
>> therefore need to configure SSH access to localhost for the hduser user
>> we created in the previous section.
>> "
>>
>> Thanks,
>> Raj
>>
>>
>>
>>
>>
>>
>> --
>> Jay Vyas
>> http://jayunit100.blogspot.com/
>>
>>
>>
>>
>> --
>> Jay Vyas
>> http://jayunit100.blogspot.com/
>>
>>
>>
>